Diagnosis of Acute Alcohol-Associated Hepatitis
AST/ALT ratio and serum bilirubin is the most helpful data for diagnosing acute alcohol-associated hepatitis. This combination provides the characteristic biochemical signature that distinguishes this condition from other liver diseases and forms the foundation of clinical diagnostic criteria.
Why AST/ALT Ratio and Bilirubin Are Diagnostic
The diagnosis of alcohol-associated hepatitis relies primarily on clinical and laboratory criteria rather than imaging or prognostic scores. The characteristic pattern includes AST/ALT ratio >1.5 (typically >2), with AST elevated to 2-6 times the upper limit of normal but rarely exceeding 400 IU/L, combined with serum bilirubin >3 mg/dL. 1, 2 This biochemical pattern has high specificity for alcohol-associated hepatitis when combined with appropriate alcohol history (>40g/day for women, >50-60g/day for men for >6 months). 1, 2
The AST/ALT ratio >2 is particularly characteristic, as it reflects the relative deficiency of pyridoxal phosphate in alcoholics and the mitochondrial damage that preferentially releases AST. 3, 4 The elevation of bilirubin >3 mg/dL defines the jaundice that is the main presenting feature of symptomatic disease. 3
Why the Other Options Are Not Primarily Diagnostic
RUQ Ultrasound Findings
- Imaging studies like ultrasound are useful for excluding biliary obstruction and other structural pathology, but they do not establish the diagnosis of alcohol-associated hepatitis. 2
- Ultrasound typically shows non-specific findings such as fatty liver and hepatomegaly, which cannot distinguish alcohol-associated hepatitis from other forms of liver disease. 3
- Imaging is a supportive tool, not a diagnostic one for this condition. 2
Maddrey's Discriminant Function and MELD
- These are prognostic scoring systems, not diagnostic tools. 3, 1
- Maddrey's DF ≥32 defines severe disease and guides treatment decisions (specifically corticosteroid therapy), but the diagnosis must already be established before calculating these scores. 3, 1
- MELD score similarly stratifies severity and predicts mortality but does not diagnose the condition. 3, 5
- You cannot use prognostic scores to make a diagnosis—they assume the diagnosis is already known. 1
INR and Albumin
- These markers reflect hepatic synthetic function and disease severity but lack diagnostic specificity. 3
- Prolonged INR and hypoalbuminemia occur in many forms of acute and chronic liver disease, not specifically alcohol-associated hepatitis. 3
- These values contribute to prognostic scores (Maddrey's DF uses INR; MELD uses INR and bilirubin) but do not establish the diagnosis. 3
Complete Diagnostic Approach
The diagnosis requires integration of three elements: 1, 2
Alcohol history: Heavy consumption (>40-60g/day) for >6 months with <60 days abstinence before jaundice onset 1, 2
Characteristic laboratory pattern:
Exclusion of other causes: Viral hepatitis, autoimmune hepatitis, drug-induced liver injury, Wilson disease, and biliary obstruction must be ruled out. 2
Common Diagnostic Pitfalls
Relying solely on clinical criteria carries a 10-50% risk of misclassification. 3 When diagnostic uncertainty exists, transjugular liver biopsy should be considered, showing macrovesicular steatosis, neutrophilic infiltration, hepatocyte ballooning, and Mallory-Denk bodies. 1, 2
Recent evidence shows clinical criteria are precise (92%) for diagnosing severe disease (MELD >20) but only 67% precise for moderate disease (MELD <20). 6 This means the biochemical pattern is most reliable when disease is severe.
Do not confuse diagnostic criteria with severity assessment. The AST/ALT ratio and bilirubin establish what the disease is; Maddrey's DF and MELD determine how severe it is. 1, 2